Field of the Invention
This technique relates to a color filter array.
Description of the Related Art
A color filter array used in an optical apparatus such as an imaging apparatus and a display apparatus is formed by exposing a photosensitive color filter film into a desired pattern, and developing and cleaning the obtained photosensitive color filter film.
In photosensitive color filter materials, residues are likely to be generated in a development step. In particular, in a case in which a photosensitive color filter material contains pigment particles for coloring, when being mixed with photosensitive resin, a gel-like form is likely to be caused due to aggregation. In the development step of the color filter film, it is therefore effective to use a two-fluid cleaning method, which is a cleaning method with high cleaning power.
The two-fluid cleaning method is conducted in the following manner for the purpose described below. After a development reaction process is performed by discharging a developer onto the exposed color filter film to form a color filter array, the two-fluid cleaning method is conducted for removing the developer and residues. In the two-fluid cleaning method, a cleaning process is performed while spraying fluid containing gas such as nitrogen and dry air and liquid such as water from the leading edge of a nozzle of a cleaning apparatus. According to the two-fluid cleaning method, residues generated during the development can be removed by physical pressure caused by droplets sprayed in an accelerated manner.
Japanese Patent Application Laid-Open No. 11-211907 discloses rotating a substrate to which a photosensitive coloring pigment resist is applied, horizontally reciprocating a nozzle, and simultaneously spraying pure water and gas from the nozzle onto the substrate.
The color filter array was thus formed by using the two-fluid cleaning method, and a highly sensitive imaging apparatus was manufactured. At this time, it was found that periodical unevenness is generated in a captured image IMG as illustrated in FIG. 7A, for example. A period P of this periodical unevenness corresponds to a range of 1 to 10 mm in an imaging region of the imaging apparatus. In light of the fact that a pixel size is 1 to 10 μm, such unevenness is not considered to be the one resulting from the configuration of pixels.
The present inventor considered in detail, and it was found that the pattern of the unevenness generated in the image captured by the imaging apparatus differs depending on the position within a wafer 100 from which chips constituting the imaging apparatus are cut out. Furthermore, as illustrated in FIG. 7B, when images obtained by respective chip ISCs are joined together so as to correspond to the positions of the chip ISCs on the wafer 100, it was found that unevenness is generated substantially concentrically from the center chip ISC of the wafer 100.